posted on 2020-10-09, 13:36authored byChao Sun, Peng Zuo, Wu Sun, Ruidi Xia, Zihao Dong, Li Zhu, Jing Lv, Guodong Deng, Linghua Tan, Yuming Dai
In
the field of energy storage, layered double hydroxides (LDHs)
have aroused researchers’ extensive attentions because of their
low cost, high theoretical specific capacitance (SC), and adjustable
interlayer structure. Notably, the appearance of single-layer or few-layer
LDHs nanosheets has addressed the puzzle of large wall thickness and
shows a large specific surface area which produces more active sites.
However, the cyclic stability of the LDHs nanosheets has been hindered,
which result from their poor conductivity, weak structural stability
and natural stacking, so the usefulness of them is limited in practice.
In this work, exfoliated two-dimensional (2D) MXene (F-MXene)/exfoliated
2D ZnMnNi LDH (F-ZnMnNi LDH) van der Waals heterostructures were successfully
fabricated by using electrostatic self-assembly between negatively
titanium carbide F-MXene nanosheets and positively charged F-ZnMnNi
LDH nanosheets. The as-prepared 2D/2D van der Waals heterostructures
integrate the advantages of F-MXene and F-ZnMnNi LDH, including outstanding
electron conductivity, stable structure, and superior redox activity.
Accordingly, the as-prepared sample exhibits ultrahigh SC of 2065
F/g at a scan rate of 5 mV/s and remarkable cycling stability with
capacitance retention of 99.8% after 100 000 cycles at a current
density of 1 A/g.